High Quality Content by WIKIPEDIA articles! A teleprinter (teletypewriter, Teletype or TTY) is a electromechanical typewriter that can be used to communicate typed messages from point to point and point to multipoint over a variety of communication channels that range from a simple electrical connection, such as a pair of wires, to the use of radio and microwave as the transmission medium. They could also serve as a command line interface to early mainframe computers and minicomputers, sending typed data to the computer with or without printed output, and printing the response from the computer.